Conclusion
Microemulsion reactor was used for lignin depolymerization in this work for the first time, and the constructed octane/n -propanol/water SFEM system has a much better efficiency by comparison with typical solvent systems where 127.1 mg g-1 of phenolic monomers is achieved under the optimized conditions. Characterizations by UV-vis spectroscopy, FT-IR spectroscopy and Cryo-SEM indicate that the solubility of lignin can be enhanced greatly in this microemulsion, and the microemulsion droplets are enlarged from 48 to 75 nm by the addition of lignin, due to the directional aggregation of lignin at the interface of microemulsion, thereby to have this lignin depolymerization process intensified. Furthermore, this system is appropriate for other organosolv lignins oxidation and the performance of it is stable even when lignin concentration is up to 40.8 g L-1. Therefore, so constructed SFEM system can give a well example for highly efficient depolymerization of lignin through a novel reactor and simple process intensification strategy.